Struct LocalDependencyIndex 

struct LocalDependencyIndex {
    sources_by_dest: FxHashMap<Local, FxHashSet<Local>>,
}

Whole-function local dependency index.

The map is intentionally directioned from destination to source: sources_by_dest[x] = {y, z} means the value of local x may have been assigned from y or z. Starting from a sink root, a reverse closure over this map finds all locals that may flow into the checked argument.

Fields

sources_by_dest: FxHashMap<Local, FxHashSet<Local>>

Implementations

impl LocalDependencyIndex

fn new(tcx: TyCtxt<'_>, def_id: DefId) -> Self

Build dependency edges from MIR assignments and call arguments.

Calls are approximated by connecting their destination to all argument locals. That is coarse but useful for wrappers such as ptr.wrapping_add(offset): the resulting pointer local depends on both the base pointer and the offset local.

fn closure_from(&self, roots: &FxHashSet<Local>) -> FxHashSet<Local>

Compute all locals that may flow into roots.

This deliberately ignores statement order; the planner only decides whether extra loop depth may be useful. The ordinary verifier remains responsible for path-ordered proof or failure once the deeper paths are enumerated.